This invention relates to vehicular tires and particularly to channeled inserts adapted for use in pneumatic tires as a replacement for pressurized air.
One of the major problems associated with pneumatic tires currently in use is that if the tire is punctured or pierced by a pointed object, the pressurized air contained therein will escape causing the tire to deflate. When this occurs, the tire has absolutely no utility until the puncture is sealed. This problem is well known to anyone who drives or owns a vehicle and is a particular problem to those who own and/or operate bicycles having high pressure pneumatic tires as are commonly found on the popular ten speed bicycles. Prior to this invention, many types of inserts and various methods and techniques have been suggested as a solution for these problems. One of these is the use of tire inserts. Examples of patents which disclose the use of tire inserts include the following U.S. Pat. Nos. 862,785; 918,846; 1,390,467; 1,819,632; and 1,506,411.
In each of the above patents, a means is disclosed whereby a rubber insert is placed within a tire casing to replace pressurized air. Each of the tubular inserts contains one or more cushioning chambers to simulate a pressurized pneumatic tire. One of the disadvantages of the inserts hereinbefore disclosed is that during use, the frictional movement of the inserts would generate heat and thereby cause deterioration of the tire casing's inner walls. Another problem is that there was no convenient means by which the prior art tire inserts could be constructed to insure a simulated pressure equivalent to the manufacturer's recommended pressure. In addition, many of the inserts disclosed in the prior art rely on the use of trapped ambient pressure to obtain a cushioning effect. In so doing, the tire can take on the characteristics of a partially flat or an improperly inflated tire when the trapped air is released by puncture.
A relatively recent innovation for preventing flat tires proposes a method for filling a pneumatic tire with a foamed rubber or plastic material and then curing the material within the tire. Upon completing the curing operation, the tire would be supported by the material introduced therein and would not not require pressurized air. The above technique requires special and costly equipment to adapt to conventionally used tires and would not thereby be readily available to the average consumer.